How to Use TMP102: Examples, Pinouts, and Specs

The TMP102, manufactured by Texas Instruments, is a high-accuracy digital temperature sensor that communicates via the I2C interface. It is designed to provide precise temperature readings in a compact package, making it ideal for a wide range of applications. With a temperature range of -40°C to +125°C and low power consumption, the TMP102 is particularly well-suited for battery-operated devices and systems requiring efficient thermal monitoring.

• Consumer electronics (e.g., smartphones, laptops)
• Industrial temperature monitoring
• HVAC systems
• Medical devices
• Battery management systems
• IoT devices and wearables

The TMP102 offers a combination of high accuracy, low power consumption, and ease of integration. Below are its key technical details:

The TMP102 is available in a 6-pin SOT563 package. Below is the pinout and description:

The TMP102 is straightforward to use in a circuit, thanks to its I2C interface. Below are the steps and considerations for integrating the TMP102 into your design.

1. Power Supply: Connect the V+ pin to a 1.4V to 3.6V power source and the GND pin to ground.
2. I2C Communication: Connect the SDA and SCL pins to the corresponding I2C lines of your microcontroller. Use pull-up resistors (typically 4.7kΩ) on both lines.
3. Address Configuration: Use the ADD0 pin to set the I2C address:
   • Connect ADD0 to GND for address 0x48.
   • Connect ADD0 to V+ for address 0x49.
4. Alert Pin (Optional): The ALERT pin can be used to trigger an interrupt when the temperature exceeds a user-defined threshold.

Below is an example of how to interface the TMP102 with an Arduino UNO to read temperature data:

#include <Wire.h> // Include the Wire library for I2C communication

#define TMP102_ADDRESS 0x48 // I2C address of the TMP102 (ADD0 connected to GND)

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Start serial communication for debugging
}

void loop() {
  float temperature = readTemperature(); // Read temperature from TMP102
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");
  delay(1000); // Wait 1 second before the next reading
}

float readTemperature() {
  Wire.beginTransmission(TMP102_ADDRESS); // Start communication with TMP102
  Wire.write(0x00); // Point to the temperature register
  Wire.endTransmission();

  Wire.requestFrom(TMP102_ADDRESS, 2); // Request 2 bytes of data
  if (Wire.available() == 2) {
    // Read the two bytes and combine them into a 12-bit value
    int16_t rawData = (Wire.read() << 8) | Wire.read();
    rawData >>= 4; // Shift to remove unused bits
    if (rawData & 0x800) { // Check if the temperature is negative
      rawData |= 0xF000; // Sign-extend for negative values
    }
    return rawData * 0.0625; // Convert to Celsius (0.0625°C per LSB)
  }
  return NAN; // Return NaN if data is unavailable
}

• Use decoupling capacitors (e.g., 0.1 µF) near the V+ pin to stabilize the power supply.
• Ensure proper pull-up resistors are used on the I2C lines.
• Avoid placing the TMP102 near heat sources to ensure accurate temperature readings.
• Use the ALERT pin for real-time temperature monitoring in critical applications.

1. No Data from TMP102

   • Cause: Incorrect I2C address or wiring.
   • Solution: Verify the ADD0 pin configuration and ensure proper connections to SDA and SCL.

2. Inaccurate Temperature Readings

   • Cause: Heat sources near the sensor or insufficient decoupling.
   • Solution: Relocate the sensor away from heat sources and add a decoupling capacitor.

3. I2C Communication Failure

   • Cause: Missing pull-up resistors or incorrect clock speed.
   • Solution: Add 4.7kΩ pull-up resistors to SDA and SCL. Ensure the I2C clock speed is 100 kHz or 400 kHz.

Q: Can the TMP102 measure negative temperatures?
A: Yes, the TMP102 can measure temperatures as low as -40°C. Negative values are represented in two's complement format.

Q: What is the maximum distance for I2C communication with the TMP102?
A: The maximum distance depends on the pull-up resistor values and the capacitance of the I2C bus. For reliable communication, keep the distance short (typically less than 1 meter).

Q: Can I use the TMP102 with a 5V microcontroller?
A: Yes, but you must use level shifters or ensure the I2C lines are pulled up to a voltage within the TMP102's operating range (1.4V to 3.6V).

Q: How do I configure the temperature alert thresholds?
A: The TMP102 allows you to set high and low temperature thresholds via its configuration registers. Refer to the TMP102 datasheet for details on register configuration.

This concludes the documentation for the TMP102. For further details, refer to the official Texas Instruments datasheet.